Updates to Team Fortress 2, Counter-Strike: Source, Day of Defeat: Source and Half-Life 2: Deathmatch have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

Source Engine Changes (TF2, DoD:S, HL2M)

• Fixed a bug which caused Windows Aero Extensions video option to always be enabled, regardless of setting. Disabling this can improve compatibility with third-party programs and overlays, but may also affect performance.
  
• Fixed SourceTV showing player counts for the game server instead of the number of clients connected to the SourceTV server
  

Team Fortress 2

• Australian Christmas has begun!
  
  • Added community-contributed winter event items
    
  • Added new Grordbort Pyro and Engineer item sets
    
  • Added the "Valve Gift Grab 2011 – TF2" achievement
    
  • Added Naughty and Nice winter keys to the Mann Co. store
    
• Added a new Valve-authored control point map: Foundry
  
  • added 12 achievements for Foundry
    
  • added achievement reward milestone reward for Foundry achievement
    
• Added UGC Highlander medals
  
• Relaxed some restrictions on what misc items can be equipped simultaneously
  
• Additional improvements for client stability
  
• Updated the localization files
  

Day of Defeat: Source

• Added the "Valve Gift Grab 2011 – DoD:S" achievement
  
• Updated the localization files
  

Counter-Strike: Source

• Added the "Valve Gift Grab 2011 – CS:S" achievement
  
• Added rate limiting for connections and added the following ConVars to support that:
  
  • sv_max_connects_sec
    
  • sv_max_connects_window
    
  • sv_max_connects_sec_global
    
• Dramatically improved the dynamic model loading system's memory usage, performance, and stability
  
• Reduced memory usage on systems running Windows XP, Windows Vista, and Windows 7
  
• Improved alt-tab handling under Windows Vista and Windows 7
  
• Fixed a client crash during demo playback
  
• Updated the localization files